Micrometric drawing instrument



Dec. 16, 1930. F. scHwARTz 1,785,500

MI CROMETR IC DRAWI N0 I NSTRUMENT Filed Feb. 11, 1927 INVENTOR FMM smm/w-z his ATTORNEY Patented Dec. 16, less FRANK sonwan'raor ivnwxonx, N. Y. 1

MICROMETRIC nnawme-Insrnumnnr I Application filed rebruary'n; 1927. serial No. 167,383,

My present invention relates generallyto drawing instruments,and has particular reference to a micrometric device for employment either asan attachment for. existing instruments or as a constituent compasses and the like. 7 7

'One object of theinvention is to provide a device which may be employed as anattachment for compasses or similar instruments,

whereby micromet'ric adj ustment is rendered possibl In the employment of ordinary compasses,

dividers, or similar instruments, it. frequently .happens that the user is deslrous of repeatedly employing thesame adjustmentJ Compasses, other than bow compasses, unless specially constructed and hence relatively expensive, are usually incapable of being locked in any particular setting;faccordingly,where a'particularsetting is to befre'tained' for-a considerable period, or to befrepeated from time to time, much annoyance and inaccuracy occurs and much time is wasted in efiecting this purpose. 1

-Itis anotherobject of the present invention to provide an attachment which will obrendered equa'lly as accurate and convenient as the bow compass type. f

Briefly, myinventioncontemplates the provision of a rigid beam so constructed as to be applicable transversely of thespread legs .of

a compass, the beam being. provided with I,

' to Figs. 1-4,:it will be observed that I have means adjustable with respect thereto for engaging the spread legsand thereby forming a triangular structure in association therewith.

Furthermore, my invention contemplates the provision of at least ,one slidable element upon the'beam,and the arrangement of means operatively interposed between said element-x and the beam for rendering. minute adjust .ment of the element, longitudinally of "the beam, possible.

my device in a form which is so simple of construct on as to render the manufacture thereof extremely inexpensive. More partic-' ularly, I contemplate employing such simple elements as wire rods and constituent parts part of beam I Fig. 5 is a view modification; viate these disadvantages and willpermit "an ordinary compass orsimilar instrument to be lar operations, from integral blanks of material.-

particular structural natures and character- Iconstructable bystampingbending, or simi- I Otherffe'atures otmy 'invention lie in the istics of the various elementsand portions,

virtue: of which a complete yet inexpensive structure results. a P

For the attainment of thetoregoing objects hereinafter appear orbe pointed out, I have illustrated several embodiments of my inventionwherein j:'

' f F ig.1 is;a front elevational view of an ordinary compass having an attachment associated-therewith and my invention;

F1g.-2"1 s a*view of the essential portion of employing the features of Fig. 1', taken from therear;

Fig. 3 ianaexploded-view. of theelements inythe left-hand 'assembly 'of Fig. 1;

r Fig. is afragmentary' perspective view of theendf of the wire beam of Fig.5;

' 'Fig. 7 is a perspective view of the modified sliding element shown in Fig. 5,; and a Fig. 8 is a perspective view of a modification of the slidable element employed in Referring to the drawings and particularly shown an'ordinary compass 20 having pivot- 'edlegs" 2 l and22. Associated with the com pass is an attachment embodying the features of my invention and comprising a beam 23 extending transversely across" the spread legs 21 and22 and forming a triangular structure infassociation therewith.. I a

"In the form. shown in Fig.1 the beam 23 is constituted of an ordinarystr'ip .of stiff It is a feature of my invention to provide wire,"andthe'en d thereof is bent, as shown more clearly in Fig; 4:, toprovide an ofiset end portion Qthavinganopening 25 there two similai to 1, showing a 5' z and such other objects of my invention as may elements 26 and each being provided with means for frictionally engaging one of the legs 21and 22. Referring more particular- 1y to Fig. 3, the structuralnature of the as-- sembly of which the element 26 forms a part will be more clcarly'understood.

The elementv 26 has a body portionwith I an opening 27 therein, one end oflthe body portion being bent to form a flange 28 adjacent to the opening 27 and the other endbeing bent to form achannel 29 adapted to accommodate the rod or beam 23 therein. The element 26 is preferably associated'with a disc 30 havingan opening 31,21 b.01t 32 ing designed to pass through the openings 31 and 27f and'to be engagedby a nut 33. The

nut 33 is preferably a squarenut and-is adapted to have one edge abut against the'flange 28 so as to prevent rotation thereof 'when the .bolt 32 isturned. In this, way, the beam 23 issecurely clamped between the channel.

29. and the disc 30, after the desiredadjnstment has been effected.

Adapted tocooperate with the opposite surface of the disc 30is a clamp. 34 having an .opening 35 to receive the bolt 32,-and having a channeled end 36 adapted to frictionally embrace the leg 21. It will'be noted that the with the second slidableelement. i Referring now to Fig. 4, it will be seen that the element 27 isprovided with an opening 37 adjacent to which a' small flange 38 is provided having ,a similar function to the flange 28 with respect to a correspondingmut 39.

The uppered'ge of .the element'27 is rolled or bent to provide two sleeves or channels 40 inwhich the beam 23 is designed :to accommodate itself. Gooperable with the opposite face'of the element 27 isaclamp 41 substantially equivalent to the clamp 34 and hav-' ing a similar channelled end 42 for the acsigned' to pass through thecIamp 41 and the element 27 and to be engaged by the nut 39.

I itself for the purpose of looking or setting a The structure so farv describedjis'usable'jby compass of the character illustrated in a fixed:desiredposition. To effect achange the setting it is not necessary to remove the device entirely, since a simple loosening of the one or both of the bolts. 32 and 43-is suf ficient to permitpivotingof'th'e clamps 34 and 41 so that the angular-relationship of.

the 1egs21-and 22 may be changed,

To permit the effecting ofla furtherand ,more minute adjustment. I provide. a poi tion 44 upon the element 27 in a position lonrgit-undinally aligned with the opening-25 in the ofiset end 24. Between the offset end 24 and the portion 44 I arrange micrometric means for minutely adjusting the element 27 longitudinally'of the beam 23. I have illustratively shown a threaded rod 45 carried by the portion 44 and extending through the opening-25, a knurled nut 46. engaging with the rod 45 on theopposite side of the end 24, and a coil spring 47 being wound about'the rod and extending between the portion 44 an'dthe end 24. V

The spring 47 will normally tend to force the elemen't27 to the left (in Fig. 1). Hence, -it will be readilyimderstood that by loosening then'ut 46, a slight motion to the left will be elfectechwhereas tightening of the nut 46 willldraw the element 27 toward theright. This movement of the element 27 is extremely slight and in the nature of a micrometric adustment. 7 During such movement, the angularity' of the leg 22 will shift to a very'slight degree, and this shifting will be permitted by the nature of the frictional engagement between the leg 22 and the element 27.

, Referring for the. moment to Fig. 8, a

modified form of element, corresponding ,to

the {element 27, is illustrated wherein the rolled portions 40 are eliminated. Vihereas .the portion 44 :was constituted inFig. 1 of v an integral tab formed by bending up an end portion of the element, in Fig.8, this tab h as been extended to the top edge of the element, thereby permitting; the provision of an open-- ing' 4-8. A icorrespondingtab is provided on the'opposite end of the element and an openthrough these openings; Furthermore, an opening 50, corresponding to theopening 37,

.has been provided incloser relationship with respect to the tab 51, thelatter' serving thus to fulfill'the function previously filled by the ment upon itself. The offset end 24 is herein I :providedby themedial portion of the'wire .commodation oftheleg 22. .A bolt 43 is deelement,andthisportion is bent as shown in Fig.6 toprovide anopening'53 corresponding to the opening 25 ofFign4. J

= In this form, theielements 26 and 27are modified to provideaccommodations for both rods 52. In 7, I have shown a fiat elementrolled' along its oppositeedges to pro- It will be'obvious that many changes in the details herein described and illustratedfor the purpose of explaining the nature of my invention maybe madebv those skilled in the art without. departing from the. spirit and scope of the invention as expressed in the apving49isprovidedin alignment with the opening 48, the beam 23 being adapted to pass pended claims. Such a construction would permit the beam to be made ofsteel and to be considerably thinner. In the embodiment illustrated, the beam is designed to be of aluminum or similar material. Furthermore, a leaf spring might be interposed between one of the flanges 67 and the beam'to enhance the stability of its movement. In the embodimcnt shown, such a spring would-be split longituclinally to provide one portion bearing upon the beam 56 and another ortion bearing upon the auxiliary beam Moreover, the sliding elements exemplified by the elements 63-, 27, etc., might be constructed in a variety of ways without departing from the spirit of the-invention. Itis therefore intended that these details be interpreted as illustrative and not in a limiting sense. i a

' Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent is l. A device of the character described com prising a beam, an element slidably mounted thereon and provided. with meansfor engage ing a leg of a drawing instrument, saidmea'ns being independent of said leg and adapted to engage the-latter at anypoint thereof, and micromet-ric means operatively interposed between the beam and said element 5 for minutely adjusting the element andleg longitudinally along the beam.

' 2. A device of the character described comtions of the beam, saidmeans including an element slidably encircling said beam and a pivotally adjustable clamp carried by said element and adapted to enclose and frictionally engage'one of said legs, and means operatively interposed between the beam and said element for minutely adjusting the latter with respect to the beam.

5. As an attachment'for a drawing instrument having pivotally adjustable legs adapted to be spread relativeto each other, a mi- .crometric device comprising awire beam for transverse application across said legs, said beam being provlded'wlth an end portion having an open'therein whose axis is spaced from thebeam and parallel thereto, means adjustable along the beam for frictionally engaging said legs in desired spread disposition, said means including an element slidably associatedwith the beam and having a portion aligned withsaid axis, and means extending through said opening and asso ciated with said aligned portion for minute- 1y adjusting the element with respect to the beam. I i

ln witness whereof, I have signed and sealed this specification this 7th day; of

February, 1927; r V

-, FBANK'SCl-IWARTZ.

prising aLbeam having an .oifset end portion,

an element slidably mountedyonthe beam and drawing instrument, said means being independent of said leg and adapted to engage I the latter at any point thereof, said element 7 having a portion longitudinally alignedwith said end portion, and micrometric .means f v operatively interposed between said aligned portions for minutely adjusting the element and'leg longitudinallyalong the beam.

, provided with means forengaginga leg'ofa 3. As an attachment for a twoelegged i spaced portions of thebeam, said means being independent of saidlegs and adapted to engage the latter at any point thereof, said means including an element slidably asso ciated with the beam,and means operatively interposed between the beam and said element for minutely adjusting the latter and attached leg with respect tothe beam.

4. As an attachment for a drawing instru ment havingpivoted unperforated legs, a-

micrometric adjusting device-comprising a rigid beam for transverse disposition across said legs, means ad ustable along the beam for attaching said legs to desired spaced p0r- 

